Part 1 of this article began with discussion of the first American power systems, when lineworkers initially encountered the hazards of working on de-energized lines. This led to early personal protective grounding (PPG) efforts using trial and error. We also reviewed Charles Dalziel’s contributions toward a greater industry understanding of dangerous current levels.

In short, Part 1 confirmed the need for PPG as a key lineworker safety precaution. In this second and final part, we will review PPG’s evolution as the industry designed and improved relevant equipment, conducted more testing and developed written standards.

1940-1970: Equipment Design and Improvements
In the 1940s, protective grounds were used sporadically depending on the utility company and the line crew foreman. It was a relatively common practice for lineworkers to make their own ground sets, using #6 soft-drawn copper and hot-line tap clamps. During this period, the industry began moving away from homemade grounding equipment in favor of equipment manufactured by companies including A.B. Chance, J.R. Kearney and Safety Live Line Co.

In the 1950s, A.B. Chance offered various PPG components. Around the same time, Safety Live Line Co. of Oakland, California, manufactured a grounding cluster that featured a removable twist-lock handle. It had been determined by this point that it is best to have the grounding conductors short-circuit the line and connect it to ground.

Further, using wood-handled sticks to install protective grounds had started to become standard. The grip-all or “shotgun stick” developed in the 1950s became popular for protective ground installation and removal. Some manufacturers made protective grounds with wood-handled sticks that were permanently attached to the grounding clamps. The sticks significantly improved safety, placing workers farther from conductors in case a hot line was grounded.

This era also saw an increased interest in testing. The “fuzzing” test procedure was included in the fourth edition of “The Lineman’s and Cableman’s Handbook,” published in 1964. The fourth edition also stated that after the test, two sets of grounds shall be placed on either side of the work area, within sight of the lineworkers.

The fifth edition of the handbook (1976) recommended using a voltage detector for testing, yet it also noted that fuzzing using “fuzz rings” could be effectively performed on higher voltages. These rings were not widely used and are now quite rare. A fuzz ring’s size and shape increased the sound level for lineworkers. It was also around this time when many power companies began providing documented rules and procedures regarding the application of personal protective grounds.

Bonneville Testing
In 1954, Bonneville Power Administration conducted comprehensive testing to evaluate the effectiveness of protective grounds in ensuring the safety of its lineworkers. The tests produced the following key findings:

• “The current practice utilized by most power companies of installing grounds on adjacent structures to the one being worked on will likely not provide adequate protection for the linemen in the event the line comes energized.”
• “The short-circuiting and grounding of all conductors at work locations, using jumpers and clamps of adequate current-carrying capacity, will likely provide sufficient protection for linemen.”

Continue reading at Incident Prevention Magazine

Read Part 1 of the series here. For more safety insights for the electric utility industry, check out how to optimize arc flash protection, information about equipment stabilization, or some great information on hand protection from electric shock.